This invention relates to improvements in the air-permeable conveyor apparatus for drying tobacco leaves free from stems (hereinafter referred to as tobacco leaves).
As usual air permeable conveyor type apparatus for drying tobacco leaves has a box-like drying chamber, through which a horizontally disposed air-permeable conveyor extends such that it is covered except for its inlet and outlet section. As tobacco leaves are conveyed on the upper run of the air-permeable conveyor, they are dried continuously by drying air circulated across the air-permeable conveyor upper run and the tobacco leaves conveyed thereby.
Tobacco leaves to be dried are supplied to the drying apparatus usually by means of a conveyor. In this case, tobacco leaves are transferred onto and conveyed on the air-permeable conveyor in an orientation parallel to the plane of the air-permeable conveyor, i.e., perpendicular to the direction of supply of drying air. Therefore, the drying air passes through the layer of tobacco leaves along complicated paths and thus encounters great resistance. The resistance offered to the flow of air is not uniform and, therefore, air passes through paths where the resistance against the flow is less, thus resulting in a lack of uniformity of drying. In addition, the overall drying efficiency is inferior.